Effect of irradiation conditions and chemical composition on radiational-damage development in steels and alloys irradiated by neutrons

Abstract

The investigation of the initiation and growth kinetics of pores, dislocation structure, and particles of phase inclusions at fluxes of 1–100 dislocation/atom leads to the following conclusions. 1. The dependence of the pore concentration in steels on the flux is described by a power law; the power-law index depends strongly on the composition of the steel and the irradiation temperature. The mean pore diameter in the initial period of irradiation varies according to the law (Kt)1/2; at large fluxes, it remains almost constant. 2. In all the steels investigated, at fluxes above 5 dislocation/atom, the total dislocation density increases according to a power law; the power-law index varies from 0.4 to 1 depending on the composition of the steel and the irradiation temperature. 3. In the initial period of irradiation, a stage of accelerated inclusion-particle initiation is observed, while at high fluxes they are seen to coalesce. The correlation of the kinetics of inclusion-particle initiation and growth with the dislocation density and the irradiation temperature has been established. 4. The effect of the chemical composition of the steel, which is particularly clearly expressed at low temperature and small fluxes, is evidently due to the action of the alloying elements either on the ability of the dislocations to capture interstitial atoms or on the mechanism of the formation of new-phase inclusions.